Mounting or carrier for blades or knives for pug mills or other mixing apparatus



Patented June 6, 1939 UNITED STATES PATENT OFFICE MOUNTING OR CARRIER FOR BLADES OR KNIVES FOR PUG MILLS OR OTHER MIX- ING APPARATUS 1 Claim.

This invention relates to blades, commonly called knives for a pug mill, used in brick-making and allied arts and in particular to a blade mounting that has the advantage of being replaceable when worn, that may be set at the angle desirable for the particular kind of clay that is being worked, which angle may be varied for individual knives and most important that each knife will be as rigid as if it were cast solid on a steel shaft.

Pug mill blades have been made both solid and adjustable with respect to the shaft that revolves them inside the casing of the mill, the latter type so far as is known at a considerable sacrifice of strength.

It is therefore an object of the present invention to produce a blade for a pug mill and an adjustable mounting therefor that is adjustable through the entire range of adjustment that may be required with various kinds of clays, yet will be as rigid in any adjusted position as if it were made integral with the shaft.

Another object of the invention is a blade and mounting construction that permits a wide vari-' ation of blade angle without resulting in objectionable interference with the traverse of clay through the mill. 1

A stillfurther object is a blade mounting that offers a minimum of obstruction to the smooth flow of plastic clay through the mill.

The invention herein resides in the arrangement and combinations of parts hereinafter disclosed.

I attain the objects of the invention by the devices illustrated in the drawing which accompanies and forms a part of this specification, in which- Fig. I is a diagrammatic representation of a pug mill provided with a central shaft I, upon which is mounted means 2, for revolving the shaft I, which is the same shaft designated by the same numeral in the other views;

Fig. II is a short section of the shaft I upon which is mounted carriers 3, to be explained in detail hereinafter; and

Fig. III is a view of Fig; II in orthographic projection.

To practice my invention, I construct a sufficient number of carriers 3 for distribution in abutting relationship lengthwise of the shaft l, preferably making the collar portion thereof, C, of such length that the entire shaft is covered inside the housing 4 of the pug mill. Each carrier is so formed, preferably by casting of the metal so that it is provided with a boss 3acontaining a pocket 5 that may be deep enough to bare the shaft I in the bottom of the pocket. This pocket is to accommodate the inner end of the knife 6 and is shown in the form of a truncated wedge as shown in plan in Fig. II, though other forms are practicable. The knives 6 are so formed that one end fits as closely as possible into the smaller end of the truncated wedge shaped pocket, yet so that it will be possible for it to be turned to diiferent angles. 10

Made integral with the boss 3a with its inside or knife supporting surface in alignment with the pocket 5, is an angular fin portion 3b, having a long leg 30 and a short leg 3d, the latter being just wide enough to come flush with the back surface thickness of the knife 6, which it supports against the load, the other side being supported in the pocket 5 and the bolt 1 is not under shear.

The leg 30 is set at the greatest angle expected to be employed as a knife setting, and provided with a bolthole 3e for the bolt '1, which binds the blade rigidly to the angular fin leg 30. To decrease the angle of attack of the knife 6 a tapered block 8 is inserted between the element and the lower end of the knife 6.

On the opposite side of the knife I prefer to place a washer 1c, that will fill the space. This washer 1c is inserted after the knife is placed in position, the tapered block 8 follows and then the bolt 1 is placed in position through the jaws If which hold the bolt head against turning.

The tapered blocks 8 are also made so that they extend down into the socket 5, and by simply loosening the nut la, a block having a different angle may be easily substituted.

To prevent rusting fast, the carrier 3 is made as an easy fit for the shaft as shown and a lug 33 serves as a key, being file fitted for easyassembly. 40

With the knife setting as shown or of equivalent construction, an exceptionally strong assembly results, without leaving any projections to interfere with longitudinal movement of the clay in the mill; it being well known that such pro- 5 jections tend to pile damp clay to a point where the flow is seriously interfered with.

The cutting edge of the knife 6 is shown with a double bevel as is common for leading into the plastic clay and it will be noted that the back- 5 ward thrust of the mass of clay is sustained by the knife 6 which is clean practically to the surface of the carrier and ofiers no projection upon which clay can pile up; the normal cavitation of the clay mass protects the other side making the element 30 and the nut 1a practically completely out of contact with the clay as is proven by the fact that they do not become brightened to any extent in use. Thus I have a pug mill knife mounting of superior rigidity securable in any desirable range of angular relationship to the axis of revolution of the shaft yet which presents almost no impediment. to the smooth forward flow of the mass of day being processed, being in that respect the equivalent of a fixed knife machine. 7

What I claim as new and desire to secure by Letters Patent, is:

A knife mounting and knife for a pug mill comand bolting through the fin, the tapered block and 10 the knife.

7 JAMES D. THOMPSON. 

